Multiple designs exist for staged combustion in gas turbines, but most are complicated assemblies consisting of a plurality of tubing and interfaces. One kind of staged combustion in gas turbines is late lean injection (“LLI”) where the LLI injectors of the air/fuel mixture are located in a combustor far down stream to achieve improved NOx performance. NOx, or oxides of nitrogen, is one of the primary undesirable air polluting emissions produced by some gas turbines which burn conventional hydrocarbon fuels. The late lean injection is also used as an air bypass, which is useful to meet carbon monoxide or CO emissions during “turn down” or low load operation.
Current late lean injection assemblies are expensive and costly for both new gas turbine units and retrofits of existing units due to the number of parts and the complexity of the fuel passages. Current late lean injection assemblies also have a high risk for fuel leakage into the compressor discharge casing, which can result in auto-ignition and be a safety hazard.